1. Field of the Invention
The present invention relates to both a method and a system for providing features throughout a network which are supported by private branch exchanges via a packet-oriented (particularly an IP (Internet Protocol) oriented) communication network.
2. Description of the Prior Art
From the product document “Sonderausgabe telcom report und Siemens Magazin Corn: ISDN im Büro—HICOM” [Special addition telecom report and Siemens magazine Corn: ISDN in the office—HICOM] Siemens AG, Berlin and Munich, 1985, especially pages 14 to 31, a private branch exchange constructed for switching information, especially for switching voice data, is known which supports a multiplicity of features such as, for example, automatic callback, call acceptance, call diversion etc. Furthermore, it is known from the product document by Siemens AG “HICOM 300 Networking”, 1991, order number A3 1001-W-A30 to connect private branch exchanges together to form one communication network which, as a rule, is private, and to provide throughout the network features available locally at a private branch exchange.
As a rule, the private branch exchanges are connected to one another via proprietary or standardized time-slot-oriented interfaces, such as an ISDN-oriented S0 or S2m interface. Accordingly, proprietary signaling protocols or standardized signaling protocols such as, for example, QSIG (Q Interface Signaling Protocol) or the ISDN-oriented signaling protocol DSS1 (Digital Subscriber System No. 1) are used for signaling the features between the private branch exchanges.
In modern communication systems, private branch exchanges are increasingly connected to one another via computer networks; e.g., a LAN (Local Area Network). As a rule, data are transmitted via these computer networks in accordance with the known packet-oriented IP (Internet Protocol). A known standard based on the IP protocol for transmitting voice, data and video communication is the H.323 protocol standardized by the ITU-T (International Telecommunication Union—Telecommunications).
To provide throughout the network the features supported by a private branch exchange via a computer network, it is necessary to convert the existing signaling protocols based on a time-slot-oriented data transmission for packet-oriented data transmission. As a rule, such a conversion is carried out by special converting devices, frequently called gateways, which must be specially adapted to the respective signaling protocol used by a private branch exchange and must be updated with each expansion of the signaling protocol. In addition, only a limited number of features are defined in the IP protocol or, respectively, the H.323 protocols that is not possible to provide throughout the network all features supported locally by a private branch exchange via a computer network supporting these protocols.
The present invention is therefore directed toward certain measures by which, throughout the network of features provided locally by a private branch exchange, a provision is made possible by a computer network.